The present invention relates generally to a keyless entry system designed to automatically operate a door lock device of an automotive vehicle without the need for any manual operations whatsoever. More specifically, the invention relates to a novel door lock device operating system which allows a possessor of a transmitter transmitting a preset code corresponding to a preset code in a vehicle-mounted controller to lock and unlock the door lock device without any manual operations. Further particularly, the invention relates to a novel and useful keyless entry system which recognizes the presence or absence of the possessor of a radio code transmitter and fully automatically locks and unlocks the door depending upon the presence or absence of the possessor.
Recently, a new keyless entry system for automotive vehicles has been proposed and put on the market. This system does not require mechanical key operation or manual entry of a preset code to operate various vehicle devices, such as the vehicle door lock, and trunk lid opener and so forth. In this keyless entry system, a pocket-portable transmitter is used as a source of a preset code signal. The transmitter generates radio waves carrying the preset code and transmits the encoded radio waves to a controller mounted on a vehicle. The controller receives the radio waves and separates the preset code from the radio waves. If the decoded code matches a preset code in the controller, the controller sends a control signal to the vehicle device to be operated.
This keyless entry system employing a radio code signal transmitter is very convenient in that it requires a single push-button operation to operate various vehicle devices such as a door lock device, a trunk lid opener and so forth. However, it would be more convenient if the vehicle devices could be operated without the need for any manual operations.